/**
 * jCarouselLite - jQuery plugin to navigate images/any content in a carousel style widget.
 * @requires jQuery v1.2 or above
 *
 * http://gmarwaha.com/jquery/jcarousellite/
 *
 * Copyright (c) 2007 Ganeshji Marwaha (gmarwaha.com)
 * Dual licensed under the MIT and GPL licenses:
 * http://www.opensource.org/licenses/mit-license.php
 * http://www.gnu.org/licenses/gpl.html
 *
 * Version: 1.0.1
 * Note: Requires jquery 1.2 or above from version 1.0.1
 */

/**
 * Creates a carousel-style navigation widget for images/any-content from a simple HTML markup.
 *
 * The HTML markup that is used to build the carousel can be as simple as...
 *
 *  <div class="carousel">
 *      <ul>
 *          <li><img src="image/1.jpg" alt="1"></li>
 *          <li><img src="image/2.jpg" alt="2"></li>
 *          <li><img src="image/3.jpg" alt="3"></li>
 *      </ul>
 *  </div>
 *
 * As you can see, this snippet is nothing but a simple div containing an unordered list of images.
 * You don't need any special "class" attribute, or a special "css" file for this plugin.
 * I am using a class attribute just for the sake of explanation here.
 *
 * To navigate the elements of the carousel, you need some kind of navigation buttons.
 * For example, you will need a "previous" button to go backward, and a "next" button to go forward.
 * This need not be part of the carousel "div" itself. It can be any element in your page.
 * Lets assume that the following elements in your document can be used as next, and prev buttons...
 *
 * <button class="prev">&lt;&lt;</button>
 * <button class="next">&gt;&gt;</button>
 *
 * Now, all you need to do is call the carousel component on the div element that represents it, and pass in the
 * navigation buttons as options.
 *
 * $(".carousel").jCarouselLite({
 *      btnNext: ".next",
 *      btnPrev: ".prev"
 * });
 *
 * That's it, you would have now converted your raw div, into a magnificient carousel.
 *
 * There are quite a few other options that you can use to customize it though.
 * Each will be explained with an example below.
 *
 * @param an options object - You can specify all the options shown below as an options object param.
 *
 * @option btnPrev, btnNext : string - no defaults
 * @example
 * $(".carousel").jCarouselLite({
 *      btnNext: ".next",
 *      btnPrev: ".prev"
 * });
 * @desc Creates a basic carousel. Clicking "btnPrev" navigates backwards and "btnNext" navigates forward.
 *
 * @option btnGo - array - no defaults
 * @example
 * $(".carousel").jCarouselLite({
 *      btnNext: ".next",
 *      btnPrev: ".prev",
 *      btnGo: [".0", ".1", ".2"]
 * });
 * @desc If you don't want next and previous buttons for navigation, instead you prefer custom navigation based on
 * the item number within the carousel, you can use this option. Just supply an array of selectors for each element
 * in the carousel. The index of the array represents the index of the element. What i mean is, if the
 * first element in the array is ".0", it means that when the element represented by ".0" is clicked, the carousel
 * will slide to the first element and so on and so forth. This feature is very powerful. For example, i made a tabbed
 * interface out of it by making my navigation elements styled like tabs in css. As the carousel is capable of holding
 * any content, not just images, you can have a very simple tabbed navigation in minutes without using any other plugin.
 * The best part is that, the tab will "slide" based on the provided effect. :-)
 *
 * @option mouseWheel : boolean - default is false
 * @example
 * $(".carousel").jCarouselLite({
 *      mouseWheel: true
 * });
 * @desc The carousel can also be navigated using the mouse wheel interface of a scroll mouse instead of using buttons.
 * To get this feature working, you have to do 2 things. First, you have to include the mouse-wheel plugin from brandon.
 * Second, you will have to set the option "mouseWheel" to true. That's it, now you will be able to navigate your carousel
 * using the mouse wheel. Using buttons and mouseWheel or not mutually exclusive. You can still have buttons for navigation
 * as well. They complement each other. To use both together, just supply the options required for both as shown below.
 * @example
 * $(".carousel").jCarouselLite({
 *      btnNext: ".next",
 *      btnPrev: ".prev",
 *      mouseWheel: true
 * });
 *
 * @option auto : number - default is null, meaning autoscroll is disabled by default
 * @example
 * $(".carousel").jCarouselLite({
 *      auto: 800,
 *      speed: 500
 * });
 * @desc You can make your carousel auto-navigate itself by specfying a millisecond value in this option.
 * The value you specify is the amount of time between 2 slides. The default is null, and that disables auto scrolling.
 * Specify this value and magically your carousel will start auto scrolling.
 *
 * @option speed : number - 200 is default
 * @example
 * $(".carousel").jCarouselLite({
 *      btnNext: ".next",
 *      btnPrev: ".prev",
 *      speed: 800
 * });
 * @desc Specifying a speed will slow-down or speed-up the sliding speed of your carousel. Try it out with
 * different speeds like 800, 600, 1500 etc. Providing 0, will remove the slide effect.
 *
 * @option easing : string - no easing effects by default.
 * @example
 * $(".carousel").jCarouselLite({
 *      btnNext: ".next",
 *      btnPrev: ".prev",
 *      easing: "bounceout"
 * });
 * @desc You can specify any easing effect. Note: You need easing plugin for that. Once specified,
 * the carousel will slide based on the provided easing effect.
 *
 * @option vertical : boolean - default is false
 * @example
 * $(".carousel").jCarouselLite({
 *      btnNext: ".next",
 *      btnPrev: ".prev",
 *      vertical: true
 * });
 * @desc Determines the direction of the carousel. true, means the carousel will display vertically. The next and
 * prev buttons will slide the items vertically as well. The default is false, which means that the carousel will
 * display horizontally. The next and prev items will slide the items from left-right in this case.
 *
 * @option circular : boolean - default is true
 * @example
 * $(".carousel").jCarouselLite({
 *      btnNext: ".next",
 *      btnPrev: ".prev",
 *      circular: false
 * });
 * @desc Setting it to true enables circular navigation. This means, if you click "next" after you reach the last
 * element, you will automatically slide to the first element and vice versa. If you set circular to false, then
 * if you click on the "next" button after you reach the last element, you will stay in the last element itself
 * and similarly for "previous" button and first element.
 *
 * @option visible : number - default is 3
 * @example
 * $(".carousel").jCarouselLite({
 *      btnNext: ".next",
 *      btnPrev: ".prev",
 *      visible: 4
 * });
 * @desc This specifies the number of items visible at all times within the carousel. The default is 3.
 * You are even free to experiment with real numbers. Eg: "3.5" will have 3 items fully visible and the
 * last item half visible. This gives you the effect of showing the user that there are more images to the right.
 *
 * @option start : number - default is 0
 * @example
 * $(".carousel").jCarouselLite({
 *      btnNext: ".next",
 *      btnPrev: ".prev",
 *      start: 2
 * });
 * @desc You can specify from which item the carousel should start. Remember, the first item in the carousel
 * has a start of 0, and so on.
 *
 * @option scrool : number - default is 1
 * @example
 * $(".carousel").jCarouselLite({
 *      btnNext: ".next",
 *      btnPrev: ".prev",
 *      scroll: 2
 * });
 * @desc The number of items that should scroll/slide when you click the next/prev navigation buttons. By
 * default, only one item is scrolled, but you may set it to any number. Eg: setting it to "2" will scroll
 * 2 items when you click the next or previous buttons.
 *
 * @option beforeStart, afterEnd : function - callbacks
 * @example
 * $(".carousel").jCarouselLite({
 *      btnNext: ".next",
 *      btnPrev: ".prev",
 *      beforeStart: function(a) {
 *          alert("Before animation starts:" + a);
 *      },
 *      afterEnd: function(a) {
 *          alert("After animation ends:" + a);
 *      }
 * });
 * @desc If you wanted to do some logic in your page before the slide starts and after the slide ends, you can
 * register these 2 callbacks. The functions will be passed an argument that represents an array of elements that
 * are visible at the time of callback.
 *
 *
 * @cat Plugins/Image Gallery
 * @author Ganeshji Marwaha/ganeshread@gmail.com
 */

(function($) {// Compliant with jquery.noConflict()
	$.fn.jCarouselLite = function(o) {
		o = $.extend({
			btnPrev : null,
			btnNext : null,
			btnGo : null,
			mouseWheel : false,
			auto : null,

			speed : 200,
			easing : null,

			vertical : false,
			circular : true,
			visible : 3,
			start : 0,
			scroll : 1,

			beforeStart : null,
			afterEnd : null
		}, o || {});

		return this.each(function() {// Returns the element collection. Chainable.

			var running = false, animCss = o.vertical ? "top" : "left", sizeCss = o.vertical ? "height" : "width";
			var div = $(this), ul = $("ul", div), tLi = $("li", ul), tl = tLi.size(), v = o.visible;

			if (o.circular) {
				ul.prepend(tLi.slice(tl - v - 1 + 1).clone()).append(tLi.slice(0, v).clone());
				o.start += v;
			}

			var li = $("li", ul), itemLength = li.size(), curr = o.start;
			div.css("visibility", "visible");

			li.css({
				overflow : "hidden",
				float : o.vertical ? "none" : "left"
			});
			ul.css({
				margin : "0",
				padding : "0",
				position : "relative",
				"list-style-type" : "none",
				"z-index" : "1"
			});
			div.css({
				overflow : "hidden",
				position : "relative",
				"z-index" : "2",
				left : "0px"
			});

			var liSize = o.vertical ? height(li) : width(li);
			// Full li size(incl margin)-Used for animation
			var ulSize = liSize * itemLength;
			// size of full ul(total length, not just for the visible items)
			var divSize = liSize * v;
			// size of entire div(total length for just the visible items)

			li.css({
				width : li.width(),
				height : li.height()
			});
			ul.css(sizeCss, ulSize + "px").css(animCss, -(curr * liSize));

			div.css(sizeCss, divSize + "px");
			// Width of the DIV. length of visible images

			if (o.btnPrev)
				$(o.btnPrev).click(function() {
					return go(curr - o.scroll);
				});

			if (o.btnNext)
				$(o.btnNext).click(function() {
					return go(curr + o.scroll);
				});

			if (o.btnGo)
				$.each(o.btnGo, function(i, val) {
					$(val).click(function() {
						return go(o.circular ? o.visible + i : i);
					});
				});

			if (o.mouseWheel && div.mousewheel)
				div.mousewheel(function(e, d) {
					return d > 0 ? go(curr - o.scroll) : go(curr + o.scroll);
				});

			if (o.auto)
				setInterval(function() {
					go(curr + o.scroll);
				}, o.auto + o.speed);

			function vis() {
				return li.slice(curr).slice(0, v);
			};

			function go(to) {
				if (!running) {

					if (o.beforeStart)
						o.beforeStart.call(this, vis());

					if (o.circular) {// If circular we are in first or last, then goto the other end
						if (to <= o.start - v - 1) {// If first, then goto last
							ul.css(animCss, -((itemLength - (v * 2)) * liSize) + "px");
							// If "scroll" > 1, then the "to" might not be equal to the condition; it can be lesser depending on the number of elements.
							curr = to == o.start - v - 1 ? itemLength - (v * 2) - 1 : itemLength - (v * 2) - o.scroll;
						} else if (to >= itemLength - v + 1) {// If last, then goto first
							ul.css(animCss, -((v) * liSize ) + "px");
							// If "scroll" > 1, then the "to" might not be equal to the condition; it can be greater depending on the number of elements.
							curr = to == itemLength - v + 1 ? v + 1 : v + o.scroll;
						} else
							curr = to;
					} else {// If non-circular and to points to first or last, we just return.
						if (to < 0 || to > itemLength - v)
							return;
						else
							curr = to;
					}// If neither overrides it, the curr will still be "to" and we can proceed.

					running = true;

					ul.animate(animCss == "left" ? {
						left : -(curr * liSize)
					} : {
						top : -(curr * liSize)
					}, o.speed, o.easing, function() {
						if (o.afterEnd)
							o.afterEnd.call(this, vis());
						running = false;
					});
					// Disable buttons when the carousel reaches the last/first, and enable when not
					if (!o.circular) {
						$(o.btnPrev + "," + o.btnNext).removeClass("disabled");
						$((curr - o.scroll < 0 && o.btnPrev) || (curr + o.scroll > itemLength - v && o.btnNext) || []).addClass("disabled");
					}

				}
				return false;
			};
		});
	};

	function css(el, prop) {
		return parseInt($.css(el[0], prop)) || 0;
	};
	function width(el) {
		return el[0].offsetWidth + css(el, 'marginLeft') + css(el, 'marginRight');
	};
	function height(el) {
		return el[0].offsetHeight + css(el, 'marginTop') + css(el, 'marginBottom');
	};

})(jQuery); 